46 CFR §42.20-75

1. (a)Summer freeboard.
   1. (1)The minimum freeboard in summer must be the freeboard derived from the tables in § 42.20-15 as modified by the corrections in §§ 42.20-3 and 42.20-5, as applicable, and §§ 42.20-20, 42.20-25, 42.20-30, 42.20-35, 42.20-60, 42.20-65 and, if applicable, § 42.20-70.
   2. (2)The freeboard in salt water, as calculated in accordance with paragraph (a)(1) of this section, but without the correction for deck line, as provided by § 42.20-35, shall not be less than 2 inches. For vessels having in position 1 hatchways with covers which do not comply with the requirements of §§ 42.15-25(d)(1), 42.15-30, or 42.15-80, the freeboard shall be not less than 6 inches.
2. (b)Tropical freeboard.
   1. (1)The minimum tropical freeboard shall be the freeboard obtained by a deduction from the summer freeboard of one forty-eighth of the summer draft measured from the top of the keel to the center of the ring of the load line mark.
   2. (2)The freeboard in salt water, as calculated in accordance with paragraph (b)(1) of this section, but without the correction for deck line, as provided by § 42.20-35, shall not be less than 2 inches. For vessels having in position 1 hatchways with covers which do not comply with the requirements of § 42.15-25(d)(1), § 42.15-30, or § 42.15-80, the freeboard shall be not less than 6 inches.
3. (c)Winter freeboard.
   1. (1)The minimum winter freeboard shall be the freeboard obtained by an addition to the summer freeboard of one forty-eighth of summer draft, measured from the top of the keel to the center of the ring of the load line mark.
4. (d)Winter North Atlantic freeboard.
   1. (1)The minimum freeboard for vessels of not more than 328 feet in length which enter any part of the North Atlantic defined in § 42.30-35 during the winter seasonal period shall be the winter freeboard plus 2 inches. For other vessels the winter North Atlantic freeboard shall be the winter freeboard.
5. (e)Fresh water freeboard.
   1. (1)The minimum freeboard in fresh water of unit density shall be obtained by deducting from the minimum freeboard in salt water:
   2. (2)Where the displacement at the summer load waterline cannot be certified, the deduction shall be one forty-eighth of summer draft, measured from the top of the keel to the center of the ring of the load line mark.